Ultra sound inconclusive

Hi, 

I found a hard lump in my neck at the beginning of October. Its hard and pops out of my spine just below my hairline when I bend my neck back or to the side. No pain. I saw GP who referred to ENT (as far as I'm aware bloods "didn't show anything" but when I've looked, various things are "high" but I have asthma/get infections so I'm always showing inflammation and increased levels of whatever). ENT said he wasn't sure, stuck a camera down my nose and said all clear there but booked an ultrasound and told me to explain the situation of how the lump moves to the person doing the scan. I went for the scan and I tried to explain about it popping in and out and he basically laughed at me and said it didn't matter as he would be able to see everything with it inside my spine. He finished the scan after a couple of minutes by saying I didn't have a lump. I corrected him and explained that I did have one that had been felt by 2 professionals. He then changed his phrasing and said that I didn't have a "problematic lump that he can see". He couldn't tell me what the lump was and just told me that there are lots of things in my neck and it would be impossible to say what it (the lump - though still refusing to call it a lump) was. Is it normal to not get a diagnosis of any sort? The ENT just wrote a letter discharging me as nothing showed up on my scan.

I've tried to carry on with life but ultimately my anxiety is such that I'm convinced it's going to get suddenly worse one day soon and that will be it. I feel like I should be able to get a diagnosis for whatever it is? Without a diagnosis to the contrary, I feel like I may as well have the diagnosis of cancer. My dad had a 'non cancerous nodule' for a few years and even though they were apparently monitoring it, it either was cancerous all along or turned cancerous and spread quickly - from diagnosis to death was less than a month only shortly before I found my lump. Should I return to GP and push for further tests - how often are things left completely undiagnosed with no further questions asked?! or go for a private, self referred MRI? I have anxiety about that too! I've read some other neck lump related posts on here and as others have said, a painless lump in the neck doesn't have any worry free diagnosis and even if non cancerous, it can grow and cause mobility issues or worse. As for growth, it's not doubled in size or anything obvious so I feel like it's hard to say if it's growing or not because my brain is amplifying it's severity daily!